J/MNRAS/528/1327 Deuterium in L1688 cold dense cores (Petrashkevich+, 2024)
Deuterium fractionation in cold dense cores in the low-mass star-forming
region L1688.
Petrashkevich I.V., Punanova A.F., Caselli P., Sipila O., Pineda J.E.,
Friesen R.K., Korotaeva M.G., Vasyunin A.I.
<Mon. Not. R. Astron. Soc. 528, 1327-1353 (2024)>
=2024MNRAS.528.1327P 2024MNRAS.528.1327P (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Interstellar medium ; Radio lines
Keywords: astrochemistry - molecular processes - stars: formation -
ISM: abundances - ISM: clouds - radio lines: ISM
Abstract:
In this work, we study deuterium fractionation in four starless cores
in the low-mass star-forming region L1688 in the Ophiuchus molecular
cloud. We study how the deuterium fraction (RD) changes with
environment, compare deuteration of ions and neutrals, core centre and
its envelope, and attempt to reproduce the observed results with a
gas-grain chemical model. We chose high and low gas density tracers to
study both core centre and the envelope. With the IRAM 30 m antenna,
we mapped N2H+(1-0), N2D+(1-0), H13CO+ (1-0) and (2-1),
DCO+(2-1), and p-NH2D(111-101) towards the chosen cores. The missing
p-NH3 and N2H+(1-0) data were taken from the literature. To measure
the molecular hydrogen column density, dust and gas temperature within
the cores, we used the Herschel/SPIRE dust continuum emission data,
the Green Bank Ammonia Survey data (NH3), and the COMPLETE survey data
to estimate the upper limit on CO depletion. We present the deuterium
fraction maps for three species towards four starless cores. Deuterium
fraction of the core envelopes traced by DCO+/H13CO+ is one order of
magnitude lower (∼0.08) than that of the core central parts traced by
the nitrogen-bearing species (∼0.5). Deuterium fraction increases with
the gas density as indicated by high deuterium fraction of high gas
density tracers and low deuterium fraction of lower gas density
tracers and by the decrease of RD with core radii, consistent with the
predictions of the chemical model. Our model results show a good
agreement with observations for RD(N2D+/N2H+) and RD(DCO+/HCO+)
and underestimate the RD(NH2D/NH3).
Description:
We mapped four cold dense cores: Oph-C-N, Oph-E-MM2, Oph-F, Oph-H-MM1,
located in the L1688 star-forming region and performed single-pointing
observations towards Oph-H-MM2 and Oph-I-MM2.
The observations were carried out with the IRAM-30m telescope on 2015
June 26-July 6 (IRAM project 009-15) and on 2016 September 20-23
(IRAM project 031-16). We observed the DCO+(2-1), H13CO+ (1-0) or
(2-1), p-NH2D(111-101), N2D+ (1-0) or (2-1), and N2H+(1-0)
The tables were used in this paper to show result.
Objects:
-----------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------
16 26 57.2 -24 31 39.0 Oph-C-N
16 27 03.1 -24 39 15.0 Oph-E-MM2
16 27 24.7 -24 40 35.3 Oph-F
16 27 58.3 -24 33 43.4 Oph-H-MM1
-----------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fdust.dat 96 8 Oph-F profile H2 and dust temperature
cntdust.dat 96 8 Oph-C-N profile H2 and dust temperature
emm2dust.dat 96 8 Oph-E-MM2 profile H2 and dust temperature
hmm1dust.dat 96 8 Oph-H-MM1 profile H2 and dust temperature
cnnmod.dat 371 8 Oph-C-N all model column densities
emm2mod.dat 371 8 Oph_E-MM2 all model column densities
fnmod.dat 371 8 Oph-F N all model column densities
hmm1mod.dat 371 8 Oph-H-MM1 all model column densities
list.dat 180 90 List of fits datacubes and maps
fits/* . 90 Individual fits datacubes and maps
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Byte-by-byte Description of file: *dust.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 au r Distance
10- 21 F12.4 cm-3 n1 Density of molecular hydrogen from profile 1
23- 46 E24.18 K Td1 Dust temperature from profile 1
48- 71 E24.18 cm-3 n2 Density of molecular hydrogen from profile 2
73- 96 E24.18 K Td2 Dust temperature from profile 2
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Byte-by-byte Description of file: cnnmod.dat emm2mod.dat fnmod.dat hmm1mod.dat
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Bytes Format Units Label Explanations
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1- 4 I4 au r Distance
6- 19 I14 cm-2 dcop-m1 Column density DCOp from model 1
21- 34 I14 cm-2 dcop-m2 Column density DCOp from model 2
36- 49 I14 cm-2 dcop-m3 Column density DCOp from model 3
51- 64 I14 cm-2 dcop-m4 Column density DCOp from model 4
66- 80 I15 cm-2 hcop-m1 Column density HCOp from model 1
82- 96 I15 cm-2 hcop-m2 Column density HCOp from model 2
98-112 I15 cm-2 hcop-m3 Column density HCOp from model 3
114-128 I15 cm-2 hcop-m4 Column density HCOp from model 4
130-141 I12 cm-2 n2dp-m1 Column density N2Dp from model 1
143-155 I13 cm-2 n2dp-m2 Column density N2Dp from model 2
157-168 I12 cm-2 n2dp-m3 Column density N2Dp from model 3
170-182 I13 cm-2 n2dp-m4 Column density N2Dp from model 4
184-196 I13 cm-2 n2hp-m1 Column density N2Hp from model 1
198-211 I14 cm-2 n2hp-m2 Column density N2Hp from model 2
213-225 I13 cm-2 n2hp-m3 Column density N2Hp from model 3
227-240 I14 cm-2 n2hp-m4 Column density N2Hp from model 4
242-256 I15 cm-2 nh2d-m1 Column density NH2D from model 1
258-272 I15 cm-2 nh2d-m2 Column density NH2D from model 2
274-287 I14 cm-2 nh2d-m3 Column density NH2D from model 3
289-303 I15 cm-2 nh2d-m4 Column density NH2D from model 4
305-320 I16 cm-2 nh3-m1 Column density NH3 from model 1
322-337 I16 cm-2 nh3-m2 Column density NH3 from model 2
339-354 I16 cm-2 nh3-m3 Column density NH3 from model 3
356-371 I16 cm-2 nh3-m4 Column density NH3 from model 4
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 21 I2 --- Nx Number of pixels along X-axis
23- 24 I2 --- Ny Number of pixels along Y-axis
26- 28 I3 --- Nz ? Number of slices
30- 51 A22 "datime" Obs.date Observation date
53- 60 F8.1 m/s bVRAD ? Lower value of VRAD interval for datacubes
62- 68 F7.1 m/s BVRAD ? Upper value of VRAD interval for datacubes
70- 77 F8.4 m/s dVRAD ? VRAD resolution
79- 81 I3 Kibyte size Size of FITS file
83-116 A34 --- FileName Name of FITS file, in subdirectory fits
118-180 A63 --- Title Title of the FITS file
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Acknowledgements:
Igor Petrashkevich, petrashkevich.igor(at)gmail.com
(End) Patricia Vannier [CDS] 08-Feb-2024